This invention relates to ultrasonic diagnostic imaging systems and, in particular, to ultrasound systems with reduced power consumption and improved reliability.
Today""s high performance ultrasound systems contain a substantial amount of sophisticated and custom circuitry which enable the systems to create high quality real-time images. This sophistication has led to the need for a complex and time-consuming boot-up procedure to initialize the system for diagnostic use each time it is turned on. The system user must wait for the boot-up procedure to conclude before the system can be used for scanning. Once the system is fully operational it can consume in excess of 1000 watts of energy on a continual basis. When it system is turned off, it proceeds through a lengthy sequence of steps to power down the system. Because of the aforementioned inconvenience and complexity of turning the ultrasound system off and on, ultrasound systems are frequently left on during periods of inactivity to avoid this delay. Sometimes an ultrasound system will be powered up continuously, and even left on overnight when it will not be used for many hours, simply as a matter of convenience. While the machine sits idle it continues to consume electricity and generate heat. It is thus desirable to minimize the power consumption of an ultrasound system during such periods of inactivity.
In accordance with the principles of the present invention, an ultrasonic diagnostic imaging system is described which can be turned off quickly and restarted and be ready for scanning in a matter of seconds. This is accomplished by allowing a processor and/or memory within the system to remain active even when the system is xe2x80x9cturned off.xe2x80x9d When the system is turned off the state of the system is minimally preserved in either volatile or nonvolatile memory so that the system can restart without having to sequence through an entire bootup procedure. In a preferred embodiment the processor has a battery backup, enabling the processor to remain active even when the ultrasound system is unplugged and being moved. When the ultrasound system arrives at its destination, diagnosis can begin at once. When the ultrasound system is idle for a period of time it automatically invokes a sequence of energy-saving procedures, including readying the system for use at a predetermined time. The use of periodically invoked low power states, even if only for seconds at a time, will over the long term save energy including the cost of air conditioning the site of the ultrasound system. Such low power states also reduce the heat dissipation and exposure of components to heat, one of the major causes of component failure. Thus an embodiment of the present invention can improve ultrasound system reliability and long term effectiveness and cost.